Hydraulic implement circuits, such as a control circuit for a bulldozer blade of a tractor, for example, employ a relief valve and a load check valve to protect or improve the performance of the circuit. The relief valve and load check valve are often bulky and require numerous bores and cavities to be formed or bored to perform the intended fuction. The cores and cavities increase the manufacturing costs of the valves. It is therefore desirable to combine the relief and load check valves in a unitary structure which is relatively compact and easy to manufacture. It is desirable to minimize the number of cavities and bores and thereby reduce manufacturing time.